Yarn feeder control mechanism for circular knitting machines

ABSTRACT

A YARN FEEDER CONTROL MECHANISM IN A CIRCULAR KNITTING MACHINE COMPRISING A SWIVELLING HOLDER SUPPORTING A PLURALITY OF YARN FEEDERS AND MEANS FOR SWIVELLING THE HOLDER DURING INTRODUCTION AND WITHDRAWAL OF FEEDERS SO AS TO AVOID FOULING OPEN NEEDLE LATCHES, HAS PROVIDED IN ASSOCIATION WITH ONE OF THE FEEDERS, MEANS FOR MOVING THAT FEEDER INDIVIDUALLY OUT OF THE RANGE OF OPEN NEEDLE LATCHES DURING ITS INTRODUCTION AND MEANS FOR SIMULTANEOUSLY PREVENTING OPERATION OF THE HOLDER SWIVELLING MEANS. SUCH PROVISION ENABLES A SUPPLEMENTARY (E.G. ELASTIC) YARN TO BE INTRODUCED WHEN SETTING UP FABRIC ON THE NEEDLES.

Sept. 21,1971 PEBERDY I r 3,606,771

YARN FEEDER CONTROL MECHANISM FOR CIRCULAR KNITTING IMCHINES Filed Sept '11, 1968 f '55 Sheets-Sheet 1 N m o 0 (DO m E m R. PEBERDY Sept. 21-, 1971 YAR FEEDER CONTROL MECHANISM FOR cmcumm KNITTING MACHINES Filed Sept. 11. 1968 5 sheets sheet 3 Sept. 21, 1971 R. PEB ERDY 3,

YARN FEEDER CONTROL MECHANISM FOR CIRCULAR KNI'I'TING MACHINES Filed Sept; 11, 1968 v s Sheets-Sheet s FIG.4.

Sept. 21, 1971 PEBERDY 3,606,771

YARN FEEDER CONTROL MECHANISM FOR CIRCULAR KNITTING MACHINES 5' Sheets-Sheet 4 Filed Sept. 11. 1968 FIG.6.

FIG.5.

S p 1'. 1-911 RPEBERDY 3,606,11

'YARN EFEEDER CONTROL MECHANISM FOR CIRCULAR KNITTING MACHINES Filed Sept. 11, 1968 5 Sheets-Sheet 5 PIC-3.7.

United States Patent 3,606,771 YARN FEEDER CONTROL MECHANISM F0 CIRCULAR KNITTING MACHINES Roland Peberdy, Wigston Magna, Leicester, England, as-

signor to The Bentley Engineering Company Limited, Leicester, England Filed Sept. 11, 1968, Ser. No. 759,151 Claims priority, application Great Britain, Sept. 27,1967, 43,894/ 67 Int. Cl. D04b /58, 15/60 US. Cl. 66-433 9 Claims ABSTRACT OF THE DISCLOSURE This invention is for improvements in circular knitting machines and is concerned more particularly with the control of yarn changes therein having reference to yarn changing mechanism of the general type as disclosed in British Patent Nos. 301,350 and 301,360 and US. Pat. No. 1,838,651, issued Dec. 29, 1931. Briefly, such yarn changing mechanism comprises a plurality of yarn feeders slidably mounted on a holder in the form of a cage, and having a series of levers, one for each feeder, for imparting feeder changing movements. Each of the feeder levers is operated by its own cam and attached rackwheel and a series of pawls mounted in a common carrier are given oscillating motion for turning the rackwheels. A selector bar is slidably mounted for co-operation with a projecting part of the pawls to prevent all or certain ones of the pawls from engaging their rackwheels, depending on the position of the selector bar.

By the mechanism just described, individual feeders may each be given sliding movement to position its yarn guiding end in any of three positions, namely an inoperative position adjacent to the respective trapper, a pick-up position for introducing a new yarn to the needles, and a normal feeding position. When a feeder is in the feeding position its nose is situated very close to the needles and the feeder cage is appropriately positioned to provide for this. This position of the cage however is not suitable for the in going feeder nose when a yarn change is being made because the ingoing feeder has to pass beyond the normal feeding position to the pick-up position in order to lay the new yarn into the hooks of the needles and could in passing the feeding position foul the needle latches as they are turning over. In order to prevent this the feeder cage is given a slight swivelling movement away from the needle cylinder whenever a feeder change is made, so that the nose of the ingoing feeder passes the feeding position just clear of the latches. The cage is then swivelled in towards the cylinder to present the ingoing yarn to the needles. A similar swivelling movement is given to the feeder cage to control the yarn of the outgoing feeder so that it can be taken by the trapper.

It will be appreciated that the swivelling of the feeder cage when a yarn change occurs not only affects the ingoing feeder but also all the other feeders in the cage.

Those feeders which are out of action and situated adjacent to their trappers are given a momentary backward and then forward movement which, although unnecessary, has no adverse effect on them or their yarns. The outgoing feeder, which is starting to move away from normal feeding position, and is still supplying yarn to the needles, is also momentarily moved away from the needles but, because the needles are knitting normally and their latches are being positively closed by the old loops, the yarn can still be taken by the latches into the hooks even though the feeder nose is momentarily moved away from the needles.

The yarn changing mechanism just referred to functions satisfactorily in connection with machines operating to produce a succession of articles, such as half hose, connected end to end. However when, as according to more recent methods of operation, machines incorporating such yarn changing mechanism are required to produce garments as individual articles cast off the needles separately, certain difficulties arise which the invention seeks to overcome.

In one method of knitting individual articles cast off separately it is required to incorporate an elastic yarn into the top of the article being knitted (e.g. a sock) at a stage in the commencement of the new article where the main knitting yarn is being fed to empty needles and there are no old loops around the needle stems to close the latches onto the yarn. At this stage the feeder for supplying the elastic yarn is moved from its trapper past the feeding positon to a pick-up position where its elastic yarn extending from the trapper can be taken by the needles together with the main yarn to be subsequently knitted into stitches on a few needles. Subsequently the elastic yarn is simply laid into the fabric without actually forming knitted stitches. When feeding elastic yarn in this manner the main yarn feeder is required to remain in the normal feeding position.

It is necessary that the elastic yarn feeder, when moving to nick-up position, should not foul the latches of the needles taking the main yarn. However, if the feeder cage is swivelled at this stage it will cause the main yarn feeder to be moved slightly away from the needles and because the needles have no yarn around their stems to positively close their latches the yarn will not be taken into the hooks and mis-feeding will result.

The invention has as one of its objects to provide for control of the actuation of one feeder in such manner that the required action is obtained without the disadvantages just mentioned.

In accordance with the invention there is provided, in or for a circular knitting machine, yarn feeder control mechanism for a plurality of yarn feeders carried by a holder which is normally given a swivelling movement as aforesaid when a feeder change is made, comprising means for selectively introducing the feeders and means whereby, when a particular one of the feeders is being introduced, the swivelling motion of the holder is avoided, and said particular one of the feeders is controlled to move clear of any open needle latches. It is thus made practicable to feed an elastic yarn through the said particular one of the feeders, for incorporation of an elastic yarn onto the top of a half hose at the stage of commencement of a new article to be knitted, while a feeder for a main yarn remains in the normal feeding position.

Conveniently the mechanism comprises feeder selecting means which, when operated to select the particular one of the feeders just referred to, avoids causing actuation of mechanism for swivelling the support.

The foregoing and other provisions of the invention will now be described by way of example with reference to 3 improved feeder change mechanism shown in the accompanying drawings in which:

FIG. 1 is a plan view of the feeder changing mechanism incorporating the present improvements and shows diagrammatically by chain dotted circles its relationship to the head of a circular knitting machine, the inner circle representing the needle cylinder;

FIG. 2 is an elevation of the mechanism viewed in the direction of arrow A in FIG. 1, showing diagrammatically in chain dotted lines some parts of the knitting machine and means for controlling the attachment.

FIG. 3 is a view of the cam assembly for controlling the elastic feeding mechanism.

FIGS. 4 and 5 are respectively a detail elevation view extracted from FIG. 2 of one feeder lever and related parts and a view of the same parts as seen from the right of FIG. 4; and

FIGS. 6 and 7 are views corresponding to FIGS. 4 and 5 but showing another feeder lever and its related parts.

The basic feeder changing mechanism to which this invention is shown as being applied, operates in a manner as disclosed in British Patent Nos. 301,350 and 301,360. The invention however may be applicable to other feeder changing mechanisms which operate in similar manner. In the drawings, only those parts of the mechanism which are necessary for an understanding of the invention are shown and only two yarn feeders are shown although in actual fact the number may be in the region of five or six.

In FIG. 2 the main bracket 1 of the feeder change mechanism can be seen located on the frame 2 of the knitting machine. The lower cambox 3 and the upper cambox 4 are indicated by chain dotted lines. Secured to the bracket 1 is a shaft 5 on which are mounted orthodox disc shaped cams for controlling the feeders and trappers. These cams are arranged in packs, one pack for controlling each feeder (or other function). A typical cam pack would comprise a feeder operating cam, a trapper operating cam and a rackwheel for rotating the two cams. Also mounted on the shaft 5 is a pawl carrier 6 which is given oscillating motion by a link 7 from the drive mechanism contained in the frame 2.

Six pawls such as 8 are shown mounted on a spindle 9 in the carrier 6. Each pawl is associated with a particular one of the individual cam packs such as 10', FIG. 1, and is urged into contact with the rackwheel attached to the cam pack by a spring (not shown). The rackwheels are made with alternating high and low teeth. A blade-like projection 8a on each of the pawls is provided to contact a selector bar 11 which is slidably mounted in slots in the side walls of the bracket 1. Also located in the side walls of the bracket is a shaft 12 (FIG. 1) which carries the feeder levers such as 13 and 19. Each lever has a cam follower such as 19a, FIG. 2, and is urged into contact with one of the disc cams by a spring (not shown). Only two feeders 14 and 15 are shown and they are slidably mounted in locating holes drilled in side walls 16a and 16b of a feeder cage 16. Each feeder has a controlling member 31 clamped to its stem and guided in one of the cam slots cut into a guide plate 160 of the feeder cage.

The operation of the feeder mechanism is as follows. When the selector bar 11 is in the extreme position indicated by the arrow B, the projection 8a of the pawls are aligned with the top heights such as 11a of the selector bar. This is an idle position where the pawls (which are oscillated continuously with their carrier 6) are prevented from engaging the teeth of their rackwheels as shown in FIG. 2. When a feeder change is desired, the selector bar 11 is moved by link and lever means 17 under the control of different height studs such as 18, FIG. 2, on the main control chain of the machine. Depending on the height of the stud used, the selector bar is shifted in the opposite direction until an appropriate slot such as 11/) is aligned with one of the pawls 8 as shown in FIG. 1.

This shifting of the selector bar is timed to take place when the pawls are out of contact with the selector bar.

On the next upward swing of the pawl carrier 6' the projection 8a of the appropriate pawl will enter the slot 11b thus allowing the tooth 8b of the pawl to engage a low cut tooth of the rackwheel of cam pack 10. The selector bar is so designed that all the other pawls are prevented from entering other slots such as 11b. Any of them may however contact the selector bar on an intermediate step such as 11c and in this position their teeth such as 8b can engage a high tooth of any rackwheel which may be presented to operate the rackwheel for withdrawal of its feeder from feeding position. Upon the next downward swing of the pawl carrier 6, cam pack 10 will be racked causing feeder lever 19* to be moved to the right from the position shown in FIG. 2 and thus allowing its associated feeder 14 to move to the position 14a (shown dotted in FIG. 1), due to the action of its spring 20, FIG. 2. In the same downward swing of the carrier 6, any cam pack associated with a feeder which is already in action will be presenting a high tooth of its rackwheel to its associated pawl, and if, as usual, the projection of such pawl is aligned with an intermediate height step of the selector bar then the pawl will engage the high tooth of its rackwheel to rack its cam pack and withdraw its feeder from feeding position to trapping position. Usually only one feeder is required to be operative at a time, and when this is the case, the arrangement of the selector bar is such that as the new feeder is introduced, the active feeder is automatically withdrawn. In the known construction, each cam pack associated with a feeder has a rack wheel attached to the two cams, one for operating the feeder and the other for operating the related trapper, as described in the aforementioned earlier patents.

The general construction and operation of the parts as so far described are orthodox and in accordance with the disclosure of the aforesaid patents. In the present case however, there is to be effected the introduction of an elastic yarn which is required to be fed to the needles at the same time as the main yarn. Therefore the design of the selector bar is such that, when the bar is positioned to allow engagement of the rackwheel associated with the elastic feeder cam pack, all other pawls are aligned with the top height of the selector bar. This ensures that the main yarn feeder will not be withdrawn even though its associated cam pack rackwheel has a high tooth presented to its racking pawl.

As has been mentioned previously, in the known construction the feeder cage 16 is capable of a limited swivelling action and this action is obtained from a cam pack and rackwheel in similar manner to that described for changing feeders. The cam pack 21, FIG. 1, operates an upstanding lever 22 (which is mounted similarly to the feeder levers on shaft 12) and through the adjustment screw 22a, a movement is transmitted to the horizontal arm 23. The arm 23, which is held by a spring against the screw 22a is secured to the bottom of a vertical spindle 24- which has a bearing in a boss provided on the main bracket 1. The feeder cage 16 is secured to the top of the spindle 24 and can thus be swivelled by turning the spindle 24 by rocking the arm 23 to move the feeder ends towards and away from the needle cylinder, all in the previously known construction.

Prior to the present invention, pivoting of the feeder cage automatically took place every time a yarn feeder was changed. The design of the selector bar was such that, only when the selector bar 11 was in its idle position, i.e. the extreme position reached by movement in the direction of arrow B, was the pawl 8/21, bluffed by the top height of the selector bar. In all other positions of the bar, the pawl 8/21 engaged the intermediate height 110 to cause swivelling of the feeder cage.

In practising the present invention and as shown in FIG. 1, the selector bar 11 is now provided with a widened projection 11d for preventing the pawl 8/21 from racking the cam pack 21. This widened projection is located on the bar in such a position that when the bar is moved to select the cam pack responsible for actuating the elastic yarn feeder, the projection 11d is aligned with the pawl 8/21 to prevent racking of the cam pack 21 and thus prevent swivelling of the feeder cage. This modification to the selector bar ensures that the main yarn feeder 15 (FIG. 1) is not disturbed when the elastic feeder 14 is introduced. Because of this, however, it is necessary to provide an independent control to the elastic feeder to prevent it fouling the needle latches as it moves across the feed position to pick-up position. This further provision of the invention will now be described.

As can be seen in FIGS. 1 and 2 the elastic yarn feeder 14 is mounted by means of an L-shaped bracket 25 on a stem 14b which is located in the feeder cage 16 in similar manner to the other feeders. It has the usual controlling member 31 guided in the plate 16c for obtaining the dipping and raising action of the feeder nose which is necessary in order to allow it to pass by the other feeders and also to position the yarn in the trapper. Sliding movement of the feeder in the cage is obtained in the usual manner from the feeder lever 19 under the control of cam pack 10. FIG. 1 shows the projection 8a of pawl 8/10 in the slot 11b of the selector bar allowing the pawl to rack the cam pack 10. The feeder 14 is shown commencing to move away from the trapper towards the pick up position 14a, shown dotted.

The L-shaped bracket 25 is fixed to the end of the stem 14b of the feeder and has the feeder nose 14 slidable in it towards and away from the needle cylinder. The feeder 14 is bent to U shape to prevent it turning on its axis and also to accommodate a compression spring 26 and a cable anchor block 27. A cable 28 is connected to the anchor block and at its other end to an arm 29 (shown most clearly in FIGS. 3 and 6) of a bell crank lever mounted on a spindle 30 in the main bracket. A follower 290 on the bell crank lever transmits movement from an extra cam a in the cam pack 10 to pull on the cable 28 and withdraw the elastic feeder nose 14 from the needle cylinder at the appropriate time to prevent it fouling the latches. Further rotation of cam 10a will relax the pull on the cable and allow the feeder 14 to move in again to the needle cylinder due to the action of the spring 26. It can thus be seen that the elastic feeder obtains all its controlling movements from one cam pack, which may be selected by the selector bar, without automatically swivelling the feeder cage since the latter is prevented from turning by engagement of the arm 23 with the adjustment screw 22a. Thus the main yarn feeder remains undisturbed.

What I claim is:

1. In a circular knitting machine, the combination comprising a plurality of yarn feeders, a holder carrying said feeders, a swivel mounting for the holder permitting it to swing to move the feeders towards and away from a position of a needle cylinder, feeder selecting means for selectively introducing the feeders into yarn feeding position, said holder slidably supporting the yarn feeders for movement therein and provided with means for altering the path thereof in transit to and from yarn feeding position, means operable to swivel said holder during introduction of a feeder, said feeder selecting means including means for withholding operation of said holder swivelling means when a particular one of the feeders is moved to feeding position, and means for additionally altering the path of said particular one of the feeders towards and away from the needle cylinder position otherwise than by movement of said holder, whereby a supplementary yarn may be introduced to feeding position by the particular one of the feeders while another yarn remains in normal feeding position via another of the yarn feeders.

2. Mechanism as claimed in claim 1 wherein the feeder selecting means comprises a movable selecting member operable to select the said particular one of the feeders and presenting means to bluff actuation of said holder swivelling means.

3. Mechanism is claimed in claim .2 wherein the feeder selecting means comprises a plurality of cam packs, racking means for operating said cam packs and a selecting member constituted by a bluff plate movable to settings in which different racking means are bluffed, and wherein the avoidance of the swivelling motion of the said holder is determined by the bluff plate when in position to select for racking a cam pack related to the said particular one of the feeders.

4. Mechanism as claimed in claim 3 comprising a cam pack for effecting swivelling motion of the holder and related racking means controlled by said bluff plate suchwise that the last named racking means is bluffed to avoid swivelling the holder when the cam pack related to the said particular one of the feeders is operated, but freed to effect swivelling of the holder for other feeder selections.

5. Mechanism as claimed in claim 1 wherein said particular one of the feeders comprises a feeder stem and a feeder nose which is movable transversely of the stem in a direction away from the position of the needle cylinder, and said additional feeder moving means moves said feeder nose firstly away from and afterwards towards the needle cylinder position during movement of said nose into the operative feeding position.

6. Mechanism according to claim 5 wherein the movement of the said feeder nose towards and away from the needle cylinder position is effected by a cam pack which effects the movement of the feeder into operative feeding position.

7. Mechanism according to claim 5 wherein the said feeder nose is spring urged to move it in the direction towards the needle cylinder position and is provided with a Bowden cable for moving it in the opposite direction.

8. Mechanism according to claim 5 wherein the said feeder nose is slidab le in a mounting unit secured to the feeder stem, to permit movement of said nose towards and away from the needle cylinder position.

9. Mechanism according to claim '8 wherein the said feeder nose is U-shaped with parallel arms slidable in bearing apertures in the mounting unit.

References Cited UNITED STATES PATENTS 1,838,651 12/1931 Bentley et a1. 2,112,501 3/1938 Manger et al. 66134 2,470,803 5/ 1949' Bristow 66-134X 2,477,495 7/1949 Peberdy 66-134X. 2,959,040 11/1960 Saunders 66134X 3,018,646 1/ 1962 Wainwright.

FOREIGN PATENTS 643,154 7/1962 Italy 66-134 ROBERT R. MACKEY, Primary Examiner 11.5. C1. X.R. 66134 

